The man wanted to shoot up the NFL’s offices on levels 5 through 8 — but “mistakenly went up the wrong elevator banks,” Mayor Eric Adams said Tuesday.

He began shooting again, killing one person, before walking down a hallway and shooting himself in the chest, police said.

Tamura, a standout football player in high school, was found with a note in his pocket that expressed an issue with the NFL and claimed he suffered from CTE — a brain injury linked to head trauma, sources said.

The scrawlings made reference to former NFL star Terry Long, the Pittsburgh Steelers offensive lineman who was diagnosed with CTE after downing antifreeze to kill himself in 2005, according to sources.